Method for the recovery of elemental sulfur in liquid form from gases containing hydrogen sulfide and the conversion of the liquid sulfur into solidified flakes



March 3, 1953 E. B. MILLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR mo SOLIDIFIED FLAKES Filed March 12, 1951 ll Sheets-Sheet l E; V g m 1- a a \a INVENTOR ERNEST B. MILLER BY W ATTORNEYS E. B. MILLER Y OF ELEMENTAL SULFUR IN LI ATTORNEYS OF THE LIQUID SULFU 1951 METHOD FOR THE RECOVER FROM GASES CONTAINING HYDROGEN SULFIDE March 3, 1953 Filed March 12,

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March 3, 1953 E. B. MILLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFlED FLAKES ll Sheets-Sheet 3 Filed March 12, 1951 INVENTOR ERNEST B. MILLER ATTORNEYS March 3, 1953 E. B. MILLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES Filed March 12, 1951 11 Sheets-Sheet 4 7 l INVENTOR ERNEST B. MILLER BY WvM ATTORNEYS INVENTOR ERNEST B. MILLER ATTORNEYS 2,630 ELEMENTAL SULFUR IN LIQUID FORM 11 Sheets-Sheet 5 MILLER B. METHOD FOR THE RECOVERY OF OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION March 3, 1953 E. B. MILLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES Filed March 12, 1951 ll Sheets-Sheet 6 FIG. IO.

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METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES Filed March 12, 1951 11 Sheets-Sheet 7 in n In 1131 .EB'

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INVENTOR ERNEST B. MILLER A ATTORNEYS I March 3, 1953 MlLLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES Filed March 12, 1951 ll Sheets-Sheet 8 F G I 5. INVENTOR I ERNEST B. MILLER BY W ATTORNEYS March 3, 1953 E. B. MILLER 2,630,374

4 METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN suwxma, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES Filed March 12, 1951 ll Sheets-Sheet 9 '2 F l 6. I6. 18? W5 30% .206 "2 200 z gr -a 3449 [87 /?0 38 I90 M7 /M 1 494 FIG. 23.

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m INVENTOR m; l I ERNEST B.M|LLER A BY-WY'M ATTORNEYS March 3, 1953 E. B. MILLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM 7 FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES IN VENTOR ERNEST B. MILLER? BY FM ATTORNEYS March 3, 1953 E. B. MILLER 2,630,374

METHOD FOR THE RECOVERY OF ELEMENTAL SULFUR IN LIQUID FORM FROM GASES CONTAINING HYDROGEN SULFIDE, AND THE CONVERSION OF THE LIQUID SULFUR INTO SOLIDIFIED FLAKES Filed March 12, 1951 11 Sheets-Sheet ll FIG. l8.

FIG. 20.

INVENTOR ERNEST B. MILLER ATTORNEYS Patented Mar. 3, 1953 UNITED STATES PATENT OF ICE.

FIED FL'AKESr Ernest B. Miller, Houston, Tex., assignor to Jefferson Lake Sulphur; Company, NewOrleans, La., a, corporation of New. Jersey Application March 12, 1951, Serial N 0. 215,178

4 Claims.

This invention relates to the recoveryof sulphur from gases containing sulphur compounds and has more particular reference to a method of and apparatus for the recovery of elemental sulphur in liquid form from gases containing hydrogen sulphide, and the conversion of. the liquid sulphur into solidified flakes.

The object of the present invention is to P vide a novel method of and apparatus for the recovery of elemental. sulphur from gases containing Hzsby catalytically desulphurizingthe gas to obtain liquid sulphur and then converting the liquid sulphur into sulphur flakes.

Another object of the invention is toprovide a novel method of and system for the continuous recovery of elemental sulphur from gases containing H28 in which a catalyst is used which is able to efiect a highly efficient conversion of H23 to H20. and sulphur and in which the catalyst, after it has become spent, due to chemical reduction of the catalytic agent or the deposition of carbon or other contaminantsfrom the gas being treated, may befully restored to its initial efficiency by reactivation with hot air.-

Another object of the invention is to provide a system, as characterized above, wherein. a series of at least three reactors are employed and the gas to be treated passes in succession through at least two reactors in'the series, before being scrubbed, and wherein a regenerating medium is passed through the third reactor in the series and wherein automatic ccntrollmeans are provided for shifting the flow through the reactors so that the last flow of the gas will be through the reactor with the freshest catalyst and the first flow of the gas will be through the reactor with the most spent catalyst.

Another object. of the invention is to provide a novel method of and system for the continuous recovery of elemental sulphur from'gases containing HzS, as characterized above, wherein the temperature rise in. each oxidation sta e is controlled by controlling the supply of oxidation gas to such stages.

Another object of the invention is to provide a novel method of and'system for the continuous recovery of elemental sulphur fromgases containing HzS, as characterized above, whereina portion of the liquid sulphur being recoveredis returned to a sulphur burner, where it is burned to. supply the oxidant required to oxidize .the HzS in the gas being processed.

Another object of the inventionlis. to provide. a system, as characterized above, including apparatus. for. continuously converting the: recovi 2 ered liquid sulphur into solidified sulphur flakes.

Another object of the. invention" is to provide a system, as characterized above, wherein the sulphur flaking. apparatus includes a plurality of rota-table water-1 jacketed annular plates; meansafor depositing: a layer of liquid sulphur superimposed upon a filmof water. on-the upper surfaces of the-plates; and. means for cracking and removing the-layers\ of deposited sulp after they, have solidified.

Other objects. and advantages of theinvention will appear in the. following, specification when considered in. connection with the accompanyingi drawings, wherein Figs. 1 and 1A. are diagrammatic elevational views of apparatus. embodying. the invention, Fig. 1A being acontinuation of Fig. 1;

Fig. 1B is a detail elevationalview of the first scrubbing tower with its appurtenances;

Figs. 2 and 2A are plan views of the apparatus shown in Figs. 1 and 1A, Fig. 2A being a continuation of Fig. 2;

Fig. 3 is. a diagrammatic. view showing the flow of. the gas to b treated, thefiow of the oxidant, and theflow ofthe regeneratin me dium through the reactors;

Fig. dis aside view, withparts broken away, of a reactor ShOWiIlg the manner in which it is connected. to the upper. and lower. headers;

Fig. 5 isa ver-tical sectional view, with parts omitted, of the reactor shown in Fig. 4.;

Fig. 6 is a sectional View taken on. the line 6-4: of Fig. 4;

Fig. 7 Ba sectional view taken on the line 1-1of Fig. .4;

Fig. 8 is a vertical sectional view, with parts broken away, of astubular container;

Fig. 9 is a plan view of the tubuiar container shown in Fig. 8;

Fig; 10 is a planview of onegroup of reactors;

Fig. 11 is a front elevational View, with parts omitted, of the group of reactors shown in Fig. 10; Fig. 12 is a vertical. sectional view through the multi-valve seat box fittin connected to #2 reactor of group I, and the outlet (inlet) valve boxes. a, b, 0 connected. thereto, taken on the line l2.-l2 of Fig. 10;

Fig. 13 is a horizontalsectional view taken on the line l3-l3 of Fig. 12;

Fig. 14 is a vertical sectional View of one of the D valves shown inFig. 3;

Fig; 15; is; an elevational view, with parts omitted, of the sulphurflaking machine;

Fig. 18 is a horizontal sectional View, with parts omitted, taken on the line l8l8 of Fig.

Fig. 19 is a perspective view of a water jacketing pan; I

Fig. 2i) is a detail view show-ing how thewater jacketing pans are secured tot'he annular plates;

Fig. 21 is a vertical sectional detail view showing the manner in which an inlet water connection is made to the pan;

Fig. 22 is a vertical sectional detail view showing the manner in which an outlet water connection is made to the pan;

Fig. 23 is an elevational detail view showing,

the manner in which a breaker is mounted;

Fig. 24 is an elevational detail view showing the breaker bar; and

Fig. 25 is a fragmentary perspective detail view showing the construction of a water spray pipe. In general, the invention comprises a method of and apparatus for the catalytic desulphurization of acidic gases such as gases containing HzS and/or CS2, the recovery of elemental sulphur therefrom in liquid form, and the conversion of the liquid sulphur into solidified flakes. The method of the present invention is similar to the method described in my copend-ing application, Ser. No. 215,181, filed March 12, 1951, for Method of Catalytic Desulphurization of Gases, in-that the H26 oxidant reaction is 'so conducted that the liberated elemental sulphur is maintained in the vapor form and subsequently condensed after passing through the catalyst. However, in the aforesaid copending application, catalyst beds are rotated through a plurality of reaction zones and a reactivation zone, whereas, in the present method, a continuous flow of the gas to be treated is directed through two or more successive reaction zones containing stationary catalyst, while a continuous flow of a heated regenerating medium is directed through an additional zone containing stationary catalyst and the flows of the gas and the regenerating medium are periodically shifted so that each ofthe several zones becomes, in succession, a reactivation zone, and in reverse order to the fiow of gases therethrough, each a successive reaction zone.

For the purpose of illustration, the invention will be described in connection with the catalytic desulphurization of sour natural gas and the recovery of elemental sulphur therefrom in flake form.

Referring now to the drawings, there is shown in Figs. 1 and 2, one embodiment of apparatus and the arrangement thereof for carrying'out the method of this invention. The apparatus shown includes a sulphur burner in which a mixture of liquid sulphur and air isburned to produce a gas of combustion having as high an $02 content as possible, preferably 19%-20%;'

a waste heat boiler 2! which utilizes the heat of the gases of combustion in the sulphur burner to generate steam for runningauxiliary machincry and other purposes; a plurality of catalytic reactors 22 (six such being shown as formed into two groups with three reactors in each group) a heater it for heating the air used to regenerate the catalyst in the reactors; a fan 24 for supplying air under pressure to the heater 23 and the sulphur burner; a pre-heater 25 for heating the sour gas tobe treated prior to its entrance into 4 the first group of reactors; a heat exchanger of intercooler 25 for adjusting the temperature of the sour gas prior to its passage through the second oxidation stage of the first group of reactors; a first scrubbing tower 2'! for separating the liquid sulphur from the treated gas; a second pre-heater 28 for heating the sour gas after its passage through the first scrubbing tower and prior to its passage through the second group of reactors; a second heat exchanger or intercooler 29 for adjusting the temperature of the sour gas prior to its passage through the second oxidation stage of the second group of reactors; a second scrubbing' tower 363 for completing the separation of the elemental liquid sulphur from the treated sour gas; a water scrubbing tower 3i where the water vapor and remaining traces of sulphur vapor in the treated gas are removed; a sulphur cooling and flaking machine 32 Where the liquid elemental sulphur is solidified and formed into sulphur flakes; and a storage hopper 33 for storing the flaked sulphur.

There is shown in diagrammatic form in Fig. 3, a reactor arrangement, and particularly a system employing six reactors which have been formed into two groups, with the reactors in each group marked #1, #2, #3, for purposes of identification.

The six reactors are identical in construction and, in general, each comprises a cylindrical chamber in which catalyst in granular form is contained in tubular containers. Each reactor is shown as having an upper manifold 34 connected to an upper multi-damper seat box 35 by a connection fitting or nipple 3%, and a lower manifold 37 connected to a lower multi-damper seat box 38 by a connection fitting or nipple 39.

The upper multi-damper seat boxes 35 of reactors #1, #2 and #3 of the first group of reactors are connected to (1) outlet (inlet) damper box fittings a, b and c, respectively, mounted in an upper gas conduit or header ii); (2) outlet (inlet) damper box fittings b, c and a, respectively, mounted in a second upper gas conduit or header 4! and (3) to outlet (inlet) damper box fittings c, a and b, respectively, mounted in an upper hot air conduit or header 42. In like manner, the lower multi-damper seat boxes 38 of reactors #1, #2, and #3 of the first group of reactors are connected to (1) outlet (inlet) damper box fittings a, b and c, respectively, mounted in a lower gas conduit or header 33; (2) outlet (inlet) damper box fittings b, c and a, respectively, mounted in a second lower gas conduit or header M; and (3) to outlet (inlet) damper box fittings c, a and b, respectively, mounted in a lower hot air conduit or header Q5.

The upper gas header i0 is connected at one end to the first pre-heater 25 and has its other end closed. The upper gas header H is connected at one endto a heat exchanger 26 and has its other end closed. The upper hot air header 42 is closed at one end and is open to the atmosphere at the other end.

The lower gas header A3 is connected at one end to the heat exchanger 26 and has its other and be a diluent to the gas. If this would be at one end to the first scrubbing tower 27 and has its other end closed. The lower hot air header 45 is closed at one end and has its other end connected to the hot air heater 23. The first scrubbing tower 21 is connected to the second pre-heater 28 by a conduit it.

The upper multi-damper seat boxes 35 of the reactors #1, #2 and #3.of the second group of.

5. reactors are connected to (1) outl'et (inlet). damper box fittings a; b" and c," respectively,

mounted in an upper'gas-conduit or; header 4'];

mounted in an upper hot air conduit or header 49; In like manner, the lower. multivalve damper boxes 38 of the reactors itl; #2 and. #31

of the second group of reactors are connected to (1) outlet (inlet) damper box fittings a, b' and c; respectively, mounted in a -lower gas: conduit or.

(inlet) damper-box fittings c; wand b, respectively, mounted in a-lower hot air conduit .or,

header 52.

The upper gas header 4'! is connectedQatsone end to the second pre-heater'28 and hasitsoth'er end' closed. The upper gasheader-e8 is connected at one end to the heat exchanger 29 and has its other end closed- The upper hot air:

header' ifi is closed .at one endrand is'opentothe atmosphere at the other end. The lower; gas header 50 is connected atone end tolthe .heat exchanger 29 and has its other end closed. The lower'gas header'iil is connected at one.:end to the second scrubbing towerr3i and hasits other. end closed. The lower hot air header 52 is closed at one end and has its otherend connected torthe hot airheater 23.

Each of the conduits 'or'h'eaders lfig'fl, 42, 43, 44; 45, 11, M3,: t9; 5D, EiandBZJare'made up-:of pipe'sections and outlet (inlet) damper boxes suitably connected together in a mannerherein'iafter to be described;

While any suitable sulphur liberating. gasor oxidant may be used,.preferably and illustrae tively, S02 is employed. andis supplied by th'e sulphurburner 20.

The sulphur burner 28 andthe waste heat boilert2l may be of any usual suitable'type. The burner 29 is. shown as having alliquidesulphur supply pipe lineetconnected.;to supply; liquid. sulphur to the burner from the secondi'scrubbing tower, and an 'air. supply pipe line .54 connected to the hot airvblower 24 for supplyingiainunder- Azconduit orsheader 55;:

pressurelto the burner. havingvalved branched conduitsz56; 51, .58:and' 59 connected thereto, is connected to the exhaust stackof the sulphurburner for supplying SOZIto thereactors. The valved branch conduits 5i5 and 5? are connected to the upper gas headers lliand ti, respectively, of the first group of reactors; the valved branch conduits Stand 59 are connected to the upper gas headers 4'! and 48, respectively, of the second group of reactors.

While the S02 produced in the sulphur burner would be composed'of appr-oximately19 %-20% of S02, the remainder would be nitrogen. This nitrogen, of course, would remain in the treated gas and be a diluent to'the gas. If this would be objectionable, there could be provided a concentrated S02 by selectively adsorbing the S02 from the above-mentioned 20% SOzmixture in a silica gel adsorber or equivalentapparatus and recovering the adsorbed SOaill concentrated form.

The system shown is designed to providefor continuous operation with two stage oxidation in each group of reactors. This is accomplished in each group by mixing a predetermined amount of gasto be treated with a predetermined proportion of 1 an oxidant or sulphur liberating 'gas, illustra- 6; tively S023. and? continuously directing: the; rel-e sultant gas mixture at anioptimum prei-ereactionr" temperature into a .first selectedzreactor;iforqex ample #1. Asithe zgas. .mixturemcomes .intogintie mate contact with thecatalyst therein, .theulst oxidation stage takes place and at least a portion of the COIltfiiIlSdiHzS. is oxidizedxtotelemental Slit? phur vapor with the liberation of. heat,. mixinglar predetermined amount of the treated gas ;,mix-.-,..

ture withan additional predetermined proportion of sulphur: liberating gas; illustratively. S02; and continuouslyudirecting the resultant gas mixture at an optimum preereaction temperature :through azsecondfselected reactor, for example #3 (2nd. oxidation stage) As thegas mixture comes into contact with ;the catalyst therein, the;2ndz:oxidation stageiakes: place and afurtherportion of the contained H2S-is oxidized 'to;.elemen-tal sul-: phur-vapor'with theliberationv of heat... Atthe. same time, aregenerating medium, such .as hot air, is being passed through thethird; reactor #2. (activation stage). As. soonas-the catalyst'in the reactor forming thefirstoxidation stage 1 in: thepresent example) is spent to.a predetermined amount, the flow. of' gas and thegregenerating, medium through thenreactors is shifted; so that the first passage of the. gas to'be treated isshifted. to reactor: #3; the last passage :of'the-gas tobetreated is shiftedto .reactorrii'ii, while-the flow-of.

. the regeneratingmedium is shifted to reactor. #1.

As soon as the catalyst inreactor #3 is spent to a predetermined amount, the flow of the gas and thexregenerating. 'mediumthroug'h the reactors is automatically; shifted toucauserrthexfirst passage; of 'the gas to be treatedtobethrough-reactor #2; the 'last passagerof' the treated gas to :be' through reactor #1, and ithepassage of. the regenerating medium to be through 'reactorz-,#3. Thiscycle-oi shifting the flow1of the gas and-theregenerating, medium through the-reactors in? each group is continuous during the operation of .the: systems Thus-each reactor in succession iszlastin thexoxidation phase; (second oxidation stage), isuthen first in the oxidation phase: (first oxidation stage), and finallyaison'theactivating phase: It should-benoted that in :each' group. of' reactors the last passage-of the gas. (second: oxidation stage) is always through the reactor shaving the freshest catalysts therein, and the flow of zthetre 3 generating medium is always through; the reactor: having 'the most sp ent catalyst therein. Ateacir shift each reactor moves one step .orphasein the cycle.

In a connection with the: foregoing, it will be noted that the arrangement and mannerl in which the-outlet (inlet) damper: box fittings: a; .b; andjc :of the headers are. connectedato the upper and lower: mu'lti-damper'seat boxes of there.- actors ineach group ofreactors is *suchxthat :in each step or phase of the cycle all ofthedampers of' one group bearing the samezletterare-open; While all of the dampers 'ofithe rem'aining' two groupsbearing thesameletterare closed. In; other words, the relation of the dampers in the three phases of each cycle are as follows: first phase, all a dampers are open, all b andc dampers closed; second phase, all e dampers are open, all a and b'dampers closed; and; thirdphase; all I)" dampers open, alla and c dampers closed. The control mechanism foropening and closing all of the a, b and c dampers in accordance with a predetermined time pattern, will hereinafter be described.

The fiow ofthe' gastobe treated; the"flow' of the medium for regenerating the catalyst "in- 7 the reactors, and the flow of the S02 will now be described with reference to the reactor arrangement, as shown diagrammatically in Fig. 3. By way of example, it will be assumed that the selective control mechanism for opening and closing the dampers, a, b and c in all of the headers have operated to close all of the b and c dampers and to open all of the a dampers in all of the headers.

The sour gas to be desulphurized is delivered, under suitable pressure of from about 5 to pounds per square inch gauge, from a source of supply (not shown) to the 1st pre-heater 25, by means of a pipe line or conduit 60. The gas is heated in the pre-heater to an optimum prereaction temperature and then passes into the upper gas header 46 where it is mixed with a predetermined proportion of sulphur liberating gas or oxidant, illustratively S02. From the upper gas header 40, the gas mixture passes through outlet damper box a, upper multi-damper seat box 35, and nipple 36 into the upper manifold 34 of reactor #1 of the first group. From the manifold, the gas mixture passes downwardly through the tubular beds of catalyst in the reactor, where it comes into intimate contact with the catalyst and an exothermic reaction takes place in which some elemental sulphur is liberated in vapor form, together with steam, in accordance with the following equation:

The treated gas passes through the reator into the lower manifold 33 and from the lower manifold through the nipple connection 39, the lower multi-damper seat box 38 into the inlet damper box a of the lower header 43, through which it passes into the first heat exchanger 26, where its temperature, which has risen in the reactor, is again adjusted to an optimum pre-reaction temperature.

From the first heat exchanger 26, the treated gas passes into the upper gas header 4|, where it is mixed with an additional predetermined proportion of S02. From-the upper gas header 4|, the gas mixture passes through outlet damper box a, upper multi-damper seat box 35, and nipple 36, into the upper manifold 34 of reactor #3 of the first group of reactors. From the upper manifold, the gas mixture passes downwardly through the tubular catalyst beds in the reactor and a reaction similar to that which took place in reactor #1 occurs.

The treated gas passes through the reactor into the lower manifold 31 and from the lower manifold through the nipple connection 39, the lower multi-damper seat box 38 into the inlet damper box a of the lower header 44, through which it passes to the bottom of the first scrubbing tower 21. The treated gas mixture, including the steam and sulphur vapor formed by the reactions in the reactors rises in the scrubbing tower against a downward fiow of molten sulphur, which condenses the sulphur vapor into molten sulphur which collects in the bottom of the scrubbing tower.

From the top of the scrubbing tower 21, the partially desulphurized gas passes through a pipe line or conduit 46 into the second pre-heater 23, where its temperature is adjusted to an optimum pro-reaction temperature.

From the second pre-heater 28, the gas passes into the upper header 4?, where it is mixed with a predetermined proportion of sulphur liberating'gas ($02). From the upper header 4? the gas mixture passes through outlet damper box at, upper multi-damper seat box 35, and nipple 36, into the upper manifold 34 of reactor #1 of the second group of reactors. From the upper manifold, the gas mixture passes downwardly through the tubular catalyst beds in the reactor and a reaction similar to that which took place in reactor #1 of the first group of reactors occurs. The treated gas passes through the reactor into the lower manifold 31 and from the lower manifold through the nipple connection 39, the lower multi-damper seat box 33 into the inlet damper box a of the lower header 50, through which it passes into the second heat exchanger 29, where its temperature, which has risen in the reactor, is again adjusted to an optimum reaction temperature. From the heat exchanger 29, the gas passes into the second upper gas header 48, where it is mixed with an additional predetermined proportion of 802. From. the header 48, the gas mixture passes through outlet damper box a, upper multi-damper seat box 35, and nipple 36, into the upper manifold 34 of reactor #3 of the second group of reactors.

From the upper manifold, the gas mixture passes downwardly through the tubular catalyst beds in the reactor and a reaction similar to that which took place in reactor #1 of the first group of reactors occurs. The treated gas mixture passes through the reactor into the lower manifold 31 and from the lower manifold passes through the nipple connection 39, the lower multi-damper seat box 38 into the inlet damper box a of the lower header 5|, through which it passes into the bottom of the second scrubbing tower 30. The treated gas mixture, from which, in the last two reactors, nearly all of the remaining sulphur has been liberated in the form of elemental sulphur vapor, rises in the scrubbing tower against a downward flow of molten sulphur which condenses the sulphur vapor into molten sulphur, which collects in the bottom of the scrubbing tower. From the top of the scrubbing tower 33, the treated gas passes through pipe line 6| into the bottom of water scrubbing tower 3|. The gas rises in the water scrubbing tower 3| against a downwardly flow of water which washes the final remaining traces of sulphur vapor from the gas. From the top of the water scrubbing tower 3|, the now sweet gas is passed through a pipe line 62 to its point of use (not shown).

As shown diagrammatically in Fig. 3, S02 passes from the sulphur burner 20, through header 55 and valved branch conduits 56, 51, 58 and 59 into the upper gas headers 43, 4|, 4'! and 4.8, respectively, where it mixes with the gas in the headers and passes with said gas into the reactors. The branch conduits are provided with valves for regulatin the amount of S02 to be admitted into the gas headers, thus permitting the temperature rise in each oxidation stage to be controlled by controlling the supply of $02 or oxidation gas to such stages.

As shown diagrammatically in Fig. 3, air for use as the regenerating medium is forced into hot air heater 23 by means of a fan or blower 24. The air is heated to a temperature of about 1006 F. in the heater and, from the heater,

passes through pipe line or conduit 63 into the lowerhot air headers 45 and 52. From the lower hot air header 45, the hot air passes through outlet damper box a, lower multi-damper box seat 38, and nipple connection 33, into the lower manifold 3? of reactor #2 of the first group of reactors.

From i the tmanifold," the hot air-passes upward throughjt-he tubular catalyst. beds in the reactor into: theupper manifold 34,; the; hotair reactivating; the:catalyst in; the beds as itpasses through. Fromthexupper-manifold 34, the hot-air passes through nipple connection 35, upper multidamper seat-box 35,;and inlet damper box fitting azinto upper hot-airheader 42: and through: the header-32 to. the atmosphere.

:From thej-lowerj hot airheaderrtii, the hot air passes :throughoutlet damper box :a, lower "multidamper'seatbox ila and nipple-connection- 39, into the lower manifoldtl ofreactor #2of: the second group ofreactors. :From. the lower manifold. 31, the hotair passes upwardly through thetubular catalyst beds in the reactor into the upper manifold 34, the:-hot -airreactivating the catalyst in thep-bedseasit' assesthrough. From the upper manifold tithe hotair passes through nipple connection-3E5, upper muiti-damper seat box 35 and-inlet 'damperwbox fitting a into upper hotair headerz w, and through the header 49 to the atmosphere.

While the foregoing descriptionhas not been concerned with the utilization of pressurized equipment/this is not a-limitation. Some pressurezwillsbe.required on the system to overcome the back-pressure due to friction. Pressure above this limitation is not necessary to successful operation. "Onrthe other hand, by allowance forthe differential pressure, a reasonable increase in the over-all operating pressures will permithandling larger'gas volumes in an apparatus, of fixedsize.

The present: method: is contrived to recover a major-:portionpf the contained sulphurin'the sour gas in a .multiestage oxidation process withoutraisingthereaction temperature in any stage above about 830 by adjusting the temperature of theadmixture of; the gas to be treated and the sulphur liberating'gas, 'illustratively S02, to an optimum pre-reaction temperature-in the range of: frOm-abQutB'ZS F; toiabout 600F; prior to the entry of the-admixture into each of the stages or reaction-zoneecand controlling the amount of SOZflCllTlliltf-ZddlltO each stage or reaction zone. However; it iscontemplatedj, that substantial portions of-the contained sulphur may be removed in the respective stages when employing pre-reaction temperatures up to about 800F., while controlling the reaction temperatures in the, stages so: thatthey do not-exceed .about. 1000 F. "in I any stage. :It will be understood,-however, that'at higher reaction;temperatures. than "above 830 F. the efficiencyrofthe conversion will: be reduced. Therefore; it is: highly preferable to practice. the method: at: relatively low reaction temperatures.

;As a" specific example, assume that the raw gas to'be treated contains 125 lbs. of H255 per 4300 cubicxfeet at pressure of lbs. gauge and at 100 F. Then, about 30% of, the initial I-I2S content of the gas can be converted into sulphur vapornin the ffirst. oxidation .stage'of the first groupzof reactors bypre-heating the gas to about 500 and mixing $02 with the. pre-heated: gas at the-.ratenof about 30; lbs.- of $02 per minute priorito the :entry of the gas. into the reactor in whichthe firstoxidationstage occurs. The temperature inithereactor will rise to from about 720F. toabout 750 F.

About 30%..01". the initial total His content ofathe gas can be converted into sulphur: Vapor inflthesecond oxidation stage of the first group of 1 reactors by cooling the gaseous admixture. deliverednfrom the first oxidation stage to about 500. then-mixin fim .with the -,coo1ed,-gaseous mixture at the. rate. of about, 30 lbs. of sOzper minute prior toits, entry1 into the reactor in which the .second oxidation stage occurs. The temperature inthe reactor will rise to from about 680 F. tog-about 710? F.

About 30% of theinitialtotal I-IzS content .of thegas can be convertedinto sulphur vapor in the first oxidation stage of-thesecond group of reactors toy-preheating the. gas after its. passage through. the first scrubbing towerto about 500 F. and mixing SOzavith the, pre-heated gas .at the rate 1of-about 30-lbs.. of- S02 per minute prior to its entryiintosthe -reactor in the second group of reactors in which the first oxidation .stage occurs. The temperature inthe reactorxwill rise to fromabout 570 F.to about 700F. Theremaining of the initialtotal Hrs content of the. gascanbeconverted into sulphur vapor in the second oxidation stageofvthe second group of reactorsby cooling the gaseous admixturedelivered. fromthe first. oxidation stage to about 500 F., then. mixingSOz with the cooled gaseous admixture: at the rate of about 11 lbs. of S02 per minute prior toitsentry into the reactor of the secondgroupof reactors in .which the second oxidation-stage occurs. .The temperature. in the reactor .willrise to from about 530:F..to about 560 F.

Obviously, with raw gas having a much lesser Has content it will .bepossible to remove all of the H28 in thafirstgroup. of reactors without raising the temperature ineitherthe first or. second oxidation .stages i above a permissible reaction temperature of from about 747 F. to about 830 F.

:It istalways advisable, however, to do as much oxidation as-possibleinthefirst stage; consistent with. theabove mentioned" reaction temperatures, so that it hasbeen found advisab1e,-when treatinga gas containingabout 15% H28, to supply oxidantgasesnto. the variousstages so as to accomplishwabout- 55%. conversion in the first stage, about.25%;in the second stage,-about 12% in thethirdstagaand 8%.in. the laststage. Since, in -the. earlier stages, the catalytic conversion can not be c-ompletedpthe reaction in these stages can bewassisted .by the presence of an excess of oxidant-gas. Thus,-to-accomplish the illustrative reactions above; it has been found convenient to supply about 75% of the total oxidant gas in the first: stage and the-remaining 25% in the secondsstage. -sThe-excess notused up *ineither of these stages isvcarried with'the gas being treated,-and is-available as needed in the last two-stages.

In connection with the-foregoing, it may be pointed out that, as the boiling point of sulphur is 832 F., :a pure. sulphur vapor would condense to liquid if cooled-below:thattemperature. In the present method, as above described, there is no concentrated sulphur at any point. In fact, the maximum concentration is about 2%, at which. concentration the sulphurvapor .Will remain in vaporzformat the pressures and temperatures employed in the process.

While it is not anecessary feature of the invention,: it may. be pointed out that, if the liberated sulphur content ofthe-treated gas becomes too high between the first and second oxidation stages of either group of-reactors, all orpart of it, maybe removed. .-This ,is readily accomplished,: for example, by suitable adjustment :of the heat exchangerswz 6 and 2 9.

' The scrubbing towersdl and 30- maybeof any suitable 1;usualtype. In :the ,particular embodiment illustrated, molten sulphur is withdrawn from the bottom of the scrubbing tower 21 through pipe line 64 by pump 65 and delivered to a sulphur cooler 66 through a pipe line 67, see Fig. 1B. From the sulphur cooler 66, the molten sulphur passes through pipe line 68 to the top of the scrubbing tower 21. The molten sulphur cascades downwardly through the scrubbing tower and is brought into intimate contact with the counter-current stream of gas, steam and elemental sulphur vapor rising through the scrubbing tower and condenses the sulphur vapor into molten sulphur which collects in the bottom of the tower. In like manner, molten sulphur is withdrawn from the bottom of the scrubbing tower 30 through a pipe line 69 by a pump and delivered to a sulphur cooler ll through a pipe line 12, see Fig. 1. From the sulphur cooler I l, the molten sulphur passes through a pipe line 13 to the top of the scrubbing tower 39 and cascades downwardly through the tower in countercurrent to the upward flow of gas, steam and sulphur vapor therein and condenses the sulphur vapor which collects in the bottom of the tower. A portion of the molten sulphur being recirculated through the two scrubbing towers, is withdrawn through a pipe line M, which is connected to a cross pipe line connecting the discharge pipe lines 69 and 13 from the sulphur coolers 66 and TI, and delivered in its molten state to the sulphur cooling and flaking machine 32, where the liquid sulphur is solidified and formed into flakes, in a manner hereinafter to be described.

The water scrubbing tower 3! may be of any suitable usual type. In the particular embodiment illustrated, water is withdrawn from the bottom of the tower 3! through a pipe line 16 by a circulating pump H, and delivered to a water cooler 13 through pipe line 19. From the water cooler 18, the water passes through pipe line 80 to the top of the tower 3| and is sprayed into the tower. The gas entering the bottom of the tower 3| passes upwardly in the counter-current flow through the water spray. The water spray condenses the water vapor or steam in the gas and removes any traces of sulphur vapor which may be contained therein, leaving the gas sweet to be discharged from the tower through pipe line 62 to its point of use.

The reactors 22 are identical in construction, the details of which are shown in Figs. 4, 5, 6 and '7. As there shown, each reactor comprises a cylindrical tank 8! having a rearwardly and downwardly sloping flat top wall 82 and a rearwardly and upwardly sloping fiat bottom wall 83. The top and bottom wall members 82 and 83 are elliptical in outline and are secured, as by bolting, to flange members 84 and 85, respectively, which are secured, as by welding, to the upper and lower peripheries of the cylindrical tank 8!. A vertically spaced pair of disc-shaped plates 85, 81 are mounted in the tank 8! with their peripheral edges secured to the wall of the tank, as by welding, to form a gas-tight joint.

The top wall member 82, the upper disc member 86, and the portion of the side wall of the tank therebetween form the upper manifold 34. An opening 88 is formed in the front wall of the upper manifold and the upper flanged connecting fitting or nipple 36 is secured therein, as by welding the inner edges of the rectangular box-like fitting to the edges of the opening 88, The bottom wall member 83, the lower disc member ill, and the portion of'the side wall of the tank threbetween form the lower manifold 31. An opening 89 is formed in the front wall'of the lower manifold and the lower flanged connecting fitting or nipple 39 is secured therein by welding the inner edges of the rectangular box-like fitting to the edges of the opening 89. The upper disc-shaped member 86 has a plurality of circular openings 99 formed therein, and the lower disc-shaped member 81 has a corresponding number of circular openings 9| formed therein. The openings 99 and 9! in the two disc-shaped members are in vertical alignment, but the openings in the bottom disc-shaped member are of less diameter than the openings in the upper disc-shaped member. A tapered tubular conduit 92, preferably made of sheet metal, extends between each circular opening in the upper discshaped member and the cOrresponding aligned opening in the lower disc-shaped member, with its upper end secured to the peripheral edge of the opening in the upper disc-shaped member and its bottom edge secured to the lower discshaped member around the circular openings therein (see Fig. 5).

Mounted within each of the conduits 92 is a tubular catalyst container 93. The catalyst containers 93 are identical in construction and, as best shown in Figs. 8 and 9, each comprises two concentric tubular screens 94, 95 held in spaced apart relation by a plurality of longitudinal radial fins 95 with the annular space between the screens closed at the bottom, as by a flanged annular plate 9?. The mesh of the screens is such as to retain a granular catalyst material 98 in the annular space between the screens. Although the invention is not limited thereto, it is preferred to employ a catalyst wherein granular silica gel, or a substance having substantially the same structure, is the carrier for the active material. Oxides of iron, copper, nickel, aluminum and manganese, or mixtures thereof may be employed as the active material. However, oxides of iron are preferred.

Mounted within the inner wire screen 94 is an inverted substantially conically shaped baiile member 99. The bafiie member is closed at its apex which extends downwardly to a point near the bottom of the container and has its upper peripheral edge suitably secured to the upper peripheral edge of the screen. Preferably, the baffle member is made of sheet metal. Each container is closed at its top, as by a cap member I99, connected to ring collars llll secured to the upper end portions of the wire screens 94, 95.

It should be noted that the annular space between the inner wall of the conduit 92 and the outer wall of the conical-shaped baiile member 99 forms an open ended duct and that the annular bed of catalyst material forms a barrier extending longitudinally across the duct (see Fig. 5).

' The diameter of the bases and the taper of the side walls of the members 92 and 99 are such that the cross sectional area of the duct formed between the two members is substantially equal at its top and bottom. The tapers of the side walls of the two members are such that a substantially uniform velocity is obtained on both sides of the barrier as fluid is transferred from the upstream side to the downstream side, regardless of the direction of flow, thereby creating a substantially constant static head over the face of the barrier, resulting in a substantially uniform distribution of the fluid through the entire barrier area. This construction insures a upward, as in the case of'the heated activating medium. "In connection with the foregoing, it may. be pointed out that the annular beds'of catalyst material are so thin that they permit velocities of about from to Ifeet per minute through the beds at 60 70 F. and atmospheric pressure.

The construction and arrangement of the upper headers and lower'headers and the manner-in which they are connected toithe upper and lower multi-damper seat boxes of the reactors in each group is identical and such-arrangement for the first group-of reactors isshowninFigsmi, 10 and 11. As there shownjtheupper gasiheader 40 is positioned above the upper multi-damper seatboxes '35 with its outlet (inlet) damperboxes .a, b and 'c connected-to the tops of the multixdamper seat boxes. of reactors "#1, #Z and't S, respectively. .Theupper header 4| 1 is positioned below the :upper multi-damperseat boxes 35 with its-outlet (inlet) damper boxes a, b andc connected to the "bottom "of the multi-damperseat boxes 35'0f reactors#3, #1 and"#2,-respectively (see'Fig. ll). "Therupper hot-air headerfM is positioned below: the 'upper'head 40 and with its outlet (inlet) damper boxesa, b and c connected 1 to the front side of. the multi-damperzseat boxes 35, :as viewed in Figs. IO-an'd" l1,'0f reactors #2, #3 and#1,respectively. Inilikevmanner, the lower: gas" header: 43 ie-positioned: above "the lower "multi-valve seat"boxes *38 with its outlet (inlet) valve boxes af'band' '0 connected to the tops of the multiedamper seatboxes'38 of reactors #1, #2 and #3, respectively. "The lower gas header 44 is :positioned below the lower multi-damper seat boxes 38 with its outlet(inlet 'damper'boxes a, b and 0 connected to the bottoms ofthe multidamper seat boxes 38'ofreacters #3, #l-and=#2, respectively (see Figs. 3 and). "The lower hot air header 45 is 'positionedbelow thelowergas header 43 and with its outlet (inlet) damper boxes a, b. and :c connected to the'front side of the multi-damper seat boxes 35, as seen inFig. 4, of reactors #2,#3 and #1, respectively (see Fig. 3).

All of the outlet (inlet) damper boxes ayb and c in allof the gas headersare identical inconstruction and all of the outlet (inlet) damper boxes 11, b and c inall of the hot air headers are identical in construction. All of the upper" and lower multi-damper seat boxes are identical in construction and each is connected-to an outlet (inletydamper box a,:or' b, arc, of the three upper manifolds or thethree lower manifolds, asthe case'may be, inthe same manner.

The details of construction of a multi-damper seat. box and the construction and arrangement of the'three out1et' in1et) damper boxes connected theretoare shown in'Figs. 12, 13 and 14. The particulanmulti-damper seat'box shown in these figures istheupper'multi-damperseat box of;reactor #Zof thezfirstgroupof reactors, "shown inffigs. l0;and .11. As: therexshown; the multidamper seat 35 is formed by: front. and rearwall members I02, Hi3, and sidewall members I04, I05 secured togetheralong their edges to forma hollow rectangular .-box1ike.structure'open at its .top and bottom. The front. and rear wall members "have "integral outwardly extending flanges; formedralongtheir top and'bottom edges and are providedzwithrrectangulareshaped openmg, flanged box-like nipples "flanged nipple] Ol'is secured to the. fiangednipple ings iili which 'lthersuitably secured, as. by Weldl06, N11. .The

36 of the reactor, as by ,having .theirhflanges bolted together to form a gasQ-tight joint. The outlet (inlet) damper box b, which forms a part of uppergas header' w, is formed by frontiand rear walls 103, .1109, "side walls I|0,.I|l, and'a .topwall I I2, secured together toform a, hollow rectangular box-like. structure open at its bottom.

The front and rear walls have aligned outwardly extending flanges .formed along :their-topand bottom :edges. Thetop .wall H2 is :removably secured. .to'. the structure, as by, bolting. .Thegside wall members have. aligned circular openings formed therein and in eachiaresuitably secured .the ends 10f .the sectionsgzof the conduit 40. (as showninFigslO and 11).

.Thetoutlet (inlet) :zdam-per box b is securedto the top of theumultiedamper seat box 35, as-by bolting the flanged bottomend of thedamperbox totthe lflangedupper :end .of the damper seat box. mrectangularzplate I I3. iszmountedpbertweenii. the damper box I) and the damper seat box 35-with its peripheral;edgeysecured :;between the connected fiangeswof 1 the two boxes. :"I he:plate l 1! 3 has a circular opening I M formed therein-and provided with an" upstanding: peripheralaflangeforming a "circular; damper :seat: 1 l5. arAn. .oscillatable, shaft H6 extends transversely of: :the dam'per, box b with cone end -..iourna1led zin :.suitable bearing .forrned: on I the, rear wall! 109; and with its :othcr end.- extendineithrough: a, bearing; ,bushing-incthe front wall 4 M8. shafti l lfirhas 1a.. longitudiinallyispaccd pair of-tparalleh-crank-arms H1 rigidlysecured thereto. A circularpda'mper mem- .ber H8 is-connected :to the-ends ofzthe crank .311 313 I ll 1 for, limited rpivotal movement, 1 as by means ofan apertured lug 1Z0 bolted between-the ends-rot theccrank .arms. .The damper. member H3 is shown aszhaving arcircular ,gasKetJIZ'I, preferably madeof asbestos and:positionedto-engagethercircularwd-amperoseat H5- when the damper menrberr l 1-8; is swung; to :closed. position.

The construction :is suchthatithe shaft H 6,- when turned..;in .one .1direction,-wil1 swing the damper :member. I I8: ontorthe; damper (seat i 15 with-the .circular gasket I12 I tightly-engagingthe .endedges of th-eseat, ;.and,"wh-entturned in the. opposite direction; willsswing the damper member off the together; as by welding, and have outwardly extending flanges termed around their top and-bot- .tom' edges. The bottom wall member is removably secured' tothestructure, as by bolting. The side wallmembers havealignecl circular openings formed therein and inwhich are uitably secured,

.as-by .welding, the ends of the sections ofthe conduit or head tl (see Fig. 11).

"The outlet (inlet) damper-boxc is secured to the'bottom of th'e-"multi damper seat .box 35; as by bolting the flanged top end of the-damper box to the'fiangedbottom end "of the multirilamper seat box. A flat'rectangular plate I2! is mounted between the-damper box cwand" the rnulti-damper seat box" 35 with its peripheraledges securedb-etween the-connected flanges or the'two boxes. The plate I21 hasa circular opening I28 formed therein and provided with a downwardly projec ing peripheral flange forming a circular valve seat 129. An oscillatable shaft I39 extends transversely of the damper box with one end journallcd in a suitable bearing formed on the rear wall of the box and with its other end ex tending through a bushing bearing in the front wall of the box. The shaft I30 carries a spaced pair of parallel crank arms I3I rigidly secured thereto. A circular damper member I32 is connected to the ends of the crank arms I3I for limited pivotal movement, as by means of an apertured lug I33 bolted between the ends of the crank arms. The construction is such that the shaft I36, when turned in one direction, will swing the damper member I 32 into engagement with the damper seat, and when the shaft is turned in the other direction, will swing the damper member off the damper seat. The damper member is also provided with a circular gasket positioned to engage the circular damper seat when the damper member is swun to closed position.

The outlet (inlet) damper box a, which for-ms a part of the upper hot air header 42, is generally similar in construction to the outlet (inlet) damper boxes I) and c, and is formed by top and bottom wall members I34, I35, side wall members I36, I31, and a front wall member I38, secured together to form a hollow, rectangular box-like structure open at its rear. The top, bottom and side wall members are suitably secured together, as by welding, and have integral outwardly extending flanges formed along their front and rear ends. The front wall member is removably secured to the structure, as by bolting. The side wall members have aligned circular openings formed therein and in which are suitably secured, as by welding, the ends of the sections of the conduit or header 4.2 (see Fig. 11).

The outlet (inlet) damper box a is secured to the front side of the vmulti-darnper seat box 35, as by bolting the flanged rear end of the damper box to the flanged nipple it carried by the front wall of the multi-damper seat box. A flat, rectangular plate I39 is mounted between the damper box a and the damper seat box 35 with its peripheral edges secured between the connected flanges of the two boxes. The plate I39 has a circular opening Mil formed therein and provided with an outwardly projecting peripheral flange forming a circular damper seat I4I.

A vertical oscillatable shaft I42 is mounted in the damper box a with one end journalled in a suitable bearing formed on the bottom wall of the box and with the other end extending through the top wall. The shaft I42 carries a spaced pair of parallel arms I43 rigidly secured thereto. A circular damper member I34 is connected to the ends of the arms I43 for limited pivotal movement, as by means of an apertured lug I45 bolted between the ends of the arms. The damper member IM is also provided with a circular gasket and is swung into closed position in engagement with the damper seat I4I when the shaft M2 is turned in one direction, and into open position out of engagement with the damper seat when the shaft N32 is turned in the opposite direction.

From the foregoing, it is apparent that the multi-damper seat box 35, which communicates with the upper manifold of the reactor by means of the nipple 35, may be placed in communication with any selected one of the conduits or heads 46, 4| and 42, by moving the damper member in the damper box of the selected conduit to open position and simultaneously moving the damper members in the other two damper boxes to closed position.

Suitable means are provided for rotating the shafts carrying the damper members. In the particular embodiment of the invention illustrated, each of the damper member shafts is shown as being connected to a reciprocating air motor I45 by means of a system of levers. Each of the motors and the arrangement of levers connecting it to a damper member shaft is identical in construction and, as shown in Fig. 11, the air motor for oscillating the damper shaft in the a damper box of header iii], comprising a cylinder I41, a piston mounted in the cylinder and having a rod I48 pivotally and slidably connected at one end to one end of a lever I49 fixedly attached to the end of the shaft III; carrying the damper member, and a pair of pipes I59, I5I, communicating with the interior of the cylinder for admitting compressed air thereto on each side of the piston. The pipes are connected, one to the head end and the other to the rod end of the cylinder and are connected in a control system hereinafter to be described, and alternately act as inlet and outlet connections to move the piston first in one direction and then in the other direction. The travel of the piston is such as to move the lever through a are. This permits the damper members to move through a 90 arc in moving from closed to open position, which results in the damper members being held at right angles to the longitudinal axis of the conduits or headers, thereby permitting them to act as bafiies to direct the flow of the fluid into the multi-damper seat box.

The apparatus, and the arrangement thereof for selectively opening and closing the dampers in each of the outlet (inlet) damper boxes is generally similar to that shown in my Patent No. 1,872,783, issued August 23, 1932, for Adsorption Systems, and is diagrammatically shown in Fig. 3. As there shown, the head end pipes I50 of all of the air motors operating the damper members in the a outlet (inlet) damper boxes are connected to a distributor pipe I52 and the rod end pipes I5I of all of the air motors operating the damper members in the a outlet (inlet) damper boxes are connected to a distributor pipe I53. In like manner, all of the head end pipes I58 of all of the 2) air motors are connected to a distributor pipe i54,'and all of the rod end pipes I5! of all of the 1) air motors are connected to a distributor pipe I55, and the head end pipes I59 of all of the 0 air motors are connected to a distributor pipe I58 and the rod end pipes iii of all of the 0 air motors are connected to a distributor pipe 51.

A source of compressed air, including a motor driven compressor (not shown) and a reservoir tank I58, is connected by a pipe 559 to valves lfill, NH and I62, each also lettered a, b and c to indicate their relation to the groups of outlet (inlet) damper box motors which they respectively control. Fig. 14 shows in detail, in section, one of these valves. As shown, it is a conventional D valve of the type used on steam engines, and the pipe 58 supplies the chamber I53 with compressed air which is delivered from the port it when the valve is in the position shown, while the port I65 is connected to the exhaust passage Ice. The D valve It? is slidable so that it can open the port 565 to the compressed, air and associate the port I64 with the exhaust. The D valve is normally held in the position shown in Fig. 14, by means of a spring I63 acting on its stem. The stem extends, as at IE9, through the other end of the casing and is connected by means of a centrally pivoted lever Ill! to a roller I1I operating on a cam I12. In Fig. 3, three cams are shown on a common shaft I13, each cam having a lobe of substantially 120 extent and each lobe radially spaced from the preceding lobe by 120. This provides that but one of the valves ISO, IBI, IE2 is open against its spring at any one time and in Fig. 3, the upper valve I60 controlling the a dampers of the reactors is shown open to permit air to be delivered to the rod ends of the cylinders I46 through the distributor pipe I53, which causes the opening of the damper members in all of the a outlet (inlet) damper boxes. The remaining valves IEiI, I52 are so held by their springs that the b and c damper members of the reactors are closed, due to air being delivered to the head ends of the cylinders I46 through distributor pipes I54 and I56, respectively, thereby holding the damper members in all of the b and outlet (inlet) damper boxes in closed position.

The shaft I13 is driven by any suitable timing mechanism I14 which will turn it a third of a revolution at definite intervals, preferably timed by the average length of time necessary to de-- activate a reactor, since activation can be performed in this time or less, if necessary.

The arrangement of the reactors so that oxidation takes place in stages, is of particular advantage in that is (1) permits more efficient use of the catalyst; (2) provides for controlling the temperature of reaction by the heat exchangers between the stages; and (3) the nearly complete removal of all traces of sulphur, due to the partially reacted gas from the 1st oxidation stage being passed through a reactor which has just been activated for the 2nd oxidation stage in each group of reactors.

The details of construction of the sulphur flaking machine 32 are shown in Figs. 15 to 25, inclusive. As there shown, a vertical rotatable open ended cylindrical member I15 having a plurality of axially spaced annular plates I16 secured thereto is mounted within a suitable structural frame, indicated generally at I11, The structural frame is formed of structural steel members and is shown as including four vertical frame members I18 having their upper end portions bent over the top of the drum and secured to a plate carrying an upper vertical guide bearing I19 for a vertical shaft I80 extending centrally of the cylinder I15 and having a lower step bearing IBI mounted on a concrete foundation block I82. Upper and lower radial arms I83 connect the shaft to the cylinder. The structural frame I11 also includes four vertical frame members I84 and three vertically spaced horizontal bracing frames I85, each formed by four structural channel members I86 having their ends secured to the vertical frame members I84, and having an angle brace I81 extending across each corner (see Fig. 16).

The diameters of the circular opening in the annular plates I16 are larger than the diameter of the cylinder I15 and the inner peripheral edge portions of the plates are secured to the cylinder, as by a plurality of circumferentially spaced L-shaped members I88 having their legs suitably secured to the cylinder and the respective plates (see Figs. 18 and 21). The. outer pcripheral edge portions of the annular plates are supported by a plurality of roller assemblies I89 carried by four vertical frame members I90 each of which is secured to the three vertically spaced angle braces I81 in each corner of the structural frame assembly and by the vertical frame members I18 (see Fig. 16).

Each of the roller assemblies is identical in construction and, as best seen in Fig. 17, comprises an upper inverted U-shaped member I9I having a roller I52 journalled therein and a lower U-shaped member I93 having a roller I94 journalled therein. The members I SI and I93 are secured to the respective frame member on which they are mounted in spaced apart relation, as by means of brackets which may be welded or bolted to the frame member.

Rotation of the cylinder and the annular plates is effected as by means of a sprocket chain I95 carried by a depending ring member I96 secured to the bottom outer edge of the bottom plate I16 (see Figs. 23 and 24). The sprocket chain meshes with a sprocket I91 mounted on the upper end of a shaft I93 driven by a motor I95; through suitable reduction gear 200 (see Figs. 15 and 23).

Each of the annular plates I16 is provided with an upstanding annular flange 20I adjacent its outer periphery and an upstanding annular flange 2E2 adjacent its inner periphery (see Figs. 11 and 24). The surfaces of the plates between the inner and outer upstanding flanges are designed to have liquid sulphur deposited thereon, as the plates are rotated, by means of a plurality of perforated horizontally extending branch conduits 2133 connected to a vertically extending header conduit 204 which is connected to the pipe line 1-4 which delivers liquid sulphur from the scrubbing tower, as above described (see Figs. 15 and 16). All of the liquid sulphur pipe lines and conduits may be steam jacketed, if desired.

In order to prevent the liquid sulphur from sticking to the plates, a plurality of horizontally extending perforated branch water conduits 2B5 are provided. Each of the branch conduits extends across one of the plates I15 and is posttioned ahead of the branch conduit 203 which deposits liquid sulphur on the plate, so that a water film may be deposited on the plate as it rotates before the sulphur is deposited. The branch water conduits are connected to a water header 2% which is connected to a source of water supply (not shown), see Figs. 15 and 16. In order to insure that a continuous thin film of water is deposited on the plates I15 and to prevent any possible flow of liquid sulphur to pass back of the perforated branch water conduits 2015, each of the conduits 205 is shown as having secured thereto a downwardly and forwardly extending generally rectangular metal lip 2B1 having a felt pad 208 suitably secured to the upper portion of its surface just below the row of perforations in the pipe (see Fig. 25).

While the thin layers of deposited liquid sulphur may be solidified by air cooling, additional means for cooling the sulphur may be provided. In the particular embodiment of the invention illustrated, additional cooling means are provided by water jacketing the bottoms of the portions of the plates I16 on which the sulphur is deposited. Each of the plates I 16 is water jacketed in the same manner and, as shown, a plurality of pans 289 (see Figs. 15, 17, 18, 19) are secured to the under surfaces of the plates. Each pan is substantially trapezoidal in shape 

1. IN THE RECOVERY OF ELEMENTAL SULPHUR IN LIQUID FORM FROM GASES CONTAINING H2S INVOLVING THE CONTACT OF A CATALYST WITH THE GAS CONTAINING H2S TO FORM SULPHUR VAPOR AND THE SUBSEQUENT CONDENSATION OF THE SULPHUR VAPOR TO FORM LIQUID SULPHUR, THE IMPROVEMENT WHICH COMPRISES MAINTAINING AT LEAST ONE BED OF CATALYST IN EACH OF TWO ZONES; MIXING A PREDETERMINED AMOUNT OF THE GAS TO BE TREATED WITH A PREDETERMINED AMOUNT OF PORTION OF SULPHUR LIBERATING GAS AND CONTINUOUSLY DIRECTING A FLOW OF THE MIXED GASES AT AN OPTIMUM PRE-REACTION TEMPERATURE THROUGH ONE OF SAID ZONES, SO THAT THE H2S IN SAID ZONE WILL BE CONVERTED INTO SULPHUR VAPOR AND STEAM; CONTINUOUSLY DIRECTING THE FLOW OF A HOT OXIDIZING MEDIUM THROUGH THE OTHER OF SAID ZONES TO REACTIVATE THE CATALYST THEREIN; PERIODICALLY SHIFTING THE FLOWS OF THE MIXTURE OF H2S CONTAINING GAS AND OXIDANT GAS AND THE OXIDIZING MEDIUM THROUGH SAID ZONES, SO THAT EACH ZONE BECOMES, IN SUCCESSION, A REACTION ZONE AND A REACTIVATING ZONE; CONTINUOUSLY WITHDRAWING THE REACTED GASEOUS MIXTURE FROM THE ZONE IN WHICH REACTION IS TAKING PLACE AND DIRECTING ITS FLOW THROUGH A CONDENSING ZONE; AND THERE CONDENSING THE SULPHUR VAPOR TO FORM LIQUID SULPHUR. 